[Computercraft] Context Menu

os.loadAPI(shell.dir().."/screen")

local mo1 = {x1=0,x2=0,y1=0,y2=0,color=colors.lime,text="green",handle= function(ca) term.setBackgroundColor(colors.lime) shell.run('clear') end}
ca = false
local ah

function def()
mo2 = {x1=mo1.x1,x2=mo1.x2,y1=mo1.y2+1,y2=mo1.y2+1,color=colors.blue,text="blue",handle= function(ca) term.setBackgroundColor(colors.blue) shell.run('clear') end}
mo3 = {x1=mo1.x1,x2=mo1.x2,y1=mo2.y2+1,y2=mo2.y2+1,color=colors.purple,text="clear",handle= function(ca) term.setBackgroundColor(colors.black) shell.run('clear') end}
mo4 = {x1=mo1.x1,x2=mo1.x2,y1=mo3.y2+1,y2=mo3.y2+1,color=colors.red,text="quit",handle= function() term.setCursorPos(1,1) error('Quitted Program') end}
contextmenu = {mo1,mo2,mo3,mo4}
end

function drawMenu()
  for i = 1,#contextmenu do
    screen.drawButton(contextmenu[i])
  end
end


while true do
if ah ~= nil then
  contextmenu[ah].handle(ca)
end
if ca then
  drawMenu()
end
local ev,btn,x,y = os.pullEvent("mouse_click")
if btn == 2 then
  screen.cls()
  mo1.x1 = x
  mo1.x2 = x+5
  mo1.y1 = y
  mo1.y2 = y
  ca = true
  def()
  drawMenu()
elseif btn == 1 then
  local tp = false
  if not ca then
    screen.cls()
  else
    screen.cls()
    for i = 1,#contextmenu do
      if screen.pressed(contextmenu[i],x,y) then
        ah = i
        contextmenu[i].handle(ca)
        ca = true
        tp = true
      end
    end
    if not tp then
      ca = false
    end
  end
end
end